dominant chord / major tonality

Five chord / dominant. Upon the fifth scale degree of the major scale we create what theorists commonly term the dominant chord. Although often found as a triad in the music, the dominant chords gets really dominant when we add it's diatonic 7th degree. Let's do that right now. Adding the seventh to the triad built on the fifth degree of the major scale. Example 5.

Easy one eh? As the name implies, the dominant chord really runs the show harmonically, both in regards to the creation of artistic tension and where the music goes tonally ( key and colorwise ). Between the third and seventh degree of the dominant seventh chord is the tension creating tritone interval. We use this tonal tension to aurally create a sense of tension ( dissonance ) which resolves when the tonic is struck ( consonance ). Termed authentic cadencing, the Five to One motion is among the most common and handy harmonic motions on our palette. Adding in the Five chord in harmonizing our first theme. Example 5.

Can you sense the tension / release dynamic between bars 67 and 68 from above? This basic ability is what makes the dominant chord the dominant chord.

Here is our second theme using the Five chord as part of the One / Four / Five chord progression. Again, a very common harmonic motion. Example 5a.

Being the dominant chord imposes a great amount of harmonic responsibility. One among many of these responsibilities is to smoothly move from one tonal center to another. This changing of keys is termed to modulate and one common and theoretically correct ( ? ) way to do it is to simply present the Five chord of whatever key we want to move to. Lets set up C major as the tonic then modulate to F major. Both tonic chords are preceded by their dominant seventh chords. Example 5b.

Sound familiar? We hear this sort of thing all the time in American music. All we are doing here is to put a word labeling a particular sound, creating a vocabulary of musical terms. Basic guide tone line melody through the 4 bars above, the Bb in measure 75 is diatonic to the key of F major yes?. And of course, being dominant, the dominant color also gets to create its own style of American music, independent of the other harmonies within the major scale. Any guesses as to which style? That's right, the blues has a major tap root into dominant harmony. And dominant is tapped into the Mixolydian mode?

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We must adjust to changing times and still hold to unchanging principles. Jimmy Carter